


Buff Beach Day

by ManOfTheInterest



Category: Ben 10 Series
Genre: Beach Sex, Beaches, F/F, Futanari, Muscle Growth, Muscles, Public Sex, Vaginal Sex
Language: English
Status: Completed
Published: 2021-02-25
Updated: 2021-02-25
Packaged: 2021-03-16 00:20:44
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,852
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29692164
Author URL: https://archiveofourown.org/users/ManOfTheInterest/pseuds/ManOfTheInterest
Summary: Gwendolyn gets more than she bargains for when she puts sunblock on Gwen at the beach.
Kudos: 6





	Buff Beach Day

**Author's Note:**

> A super-short, super-hastily done request for a friend, involving Gwen muscle growth, and featuring a character named Gwendolyn. Basically an alternate-universe goth version of Gwen with black hair, black eyeshadow, black lipstick, and a monster cock.
> 
> Pic is by Wobbleblot.  
> https://twitter.com/WobbleblotArt/status/1355257725735866370

The scene was awash with intense, vivid sensations. The loud, echoing crashes of the white waves against the golden shore. The blinding glare of the sun high in the sky. The scorching heat of the surrounding summer air. It was far from what Gwendolyn would consider “comfortable,” and even further from what she would consider ideal. Regardless, despite the unamused look permanently stitched onto her makeup-infused face, she was generous enough to indulge Gwen and let the both of them take a trip to the beach for the day. However, now that they were there, treading the sand and searching for an ideal location to set down their belongings, she was having second thoughts.

“Hey, this looks like a great spot! Get the shade and chairs set up, we’ll be right next to the water when the tide comes back in,” Gwen announced cheerfully, calling Gwendolyn over to where she was standing. Gwendolyn sighed and hauled all of their bags and equipment to the spot she had designated, setting them down harshly and finally giving her arms and back a break.

“Couldn’t you have bothered to carry some of our stuff?” Gwendolyn asked, clearly displeased.

“Oh, c’mon, it wasn’t that heavy. Now, help me lay out the towels. This sand is hot!” Gwen said, reaching into the largest of their bags and pulling out two large towels, blue and gray. She laid them down next to each other, and then promptly spun around and lay down on the blue towel, sighing happily. “Ahh, that’s better!” she said, wiggling her toes.

“So… what are we supposed to do once we’ve got everything set up, anyway?” Gwendolyn asked, sitting down on her towel adjacent to Gwen. To say Gwendolyn wasn’t much of an outdoors person was a bit of an understatement, so she was very unfamiliar with most of the activities one associated with beach-going. Gwen gave her an annoyed look in response to this question.

“Well, I don’t know about you, but I’m going to take a swim. The water looks really good today,” Gwen said, pointing towards the ocean. “Oh, that reminds me…” She suddenly lay flat on the ground and closed her eyes. “Could you get some sunblock on me before I go in?”

 _“Why, can’t you?”_ was the first thing that came to Gwendolyn’s mind when she was asked this question. However, despite her overall displeasure towards the current situation, she could never pass up the opportunity to lay her hands on Gwen’s supple, smooth preteen body, especially not when said body was covered with nothing else beyond a skimpy blue bikini. So, instead, she said “Sure.”

“Thanks…” Gwen responded, grinning. Gwendolyn reached into another bag and pulled out a tube of sun lotion, squirted some out, lathered it in her hands, and then got to work on Gwen’s body. She ran her hands along the length of her torso, caressing the gentle curves and creases of her thin, cute waist. She almost spent too much time getting the cold white cream on Gwen’s waist, as her eyes forced her to admire it for just a little bit longer. Eventually, though, she managed to break away and moved on to her legs. Her long, slim, tender legs. As Gwendolyn carefully rubbed the sunblock into Gwen’s smooth skin, she began to notice that her flesh was becoming noticeably less soft as she continued to rub it. It started to look, and feel, more rigid and thick, and even appeared to be… growing? Gwendolyn paused for just a moment, and saw that Gwen’s previously thin legs now looked more toned than any pair of limbs Gwendolyn had seen in her entire life. They were like the legs of a professional bodybuilder, and they looked like they were still getting bigger. Not just bigger, but longer, too. Gwen's body was gaining just as much height as she was girth, forcing Gwendolyn to constantly shift herself just to keep her position over Gwen's body. Needless to say, she was shocked.

“Hey, hurry it up!” Gwen ordered, snapping her fingers. Gwendolyn broke her eyes off of Gwen’s thickening legs and moved back up to her torso, which, much to her surprise, was also growing. In place of Gwen’s flat tummy was an impressively well-defined eight-pack, acting as the centerfold for the increasingly-dense masses of muscle that were taking up the rest of her torso. The only exception to these developments were in her chest, which was also growing, but not with muscle, as Gwendolyn might be led to expect. Instead, Gwen appeared to be rapidly developing breasts, and large ones, at that. A pair of perky DDs, at least, that put the preteen mosquito bites that had once been there to shame. Her nipples had even grown larger, too, and were creating harsh creases in the strained fabric of her bikini top. As she watched this unfold, Gwendolyn was oblivious to the fact that she had already started to lather up Gwen’s arms with sunblock at the same time, too. Once she brought her attention to her arms, Gwendolyn saw that they too were growing more muscular, thickening up and becoming so toned and well-defined, they hardly resembled their original forms.

“Uh… G-Gwen, I think you’re-” Gwendolyn began, nervously.

“Done? Yeah, me too. Let me roll over so you can do my back,” Gwen said, forcing Gwendolyn to move backwards hastily as her enormous, muscular body turned itself over, revealing her back to Gwendolyn. Much of it had already swollen up with muscle, and Gwendolyn knew the sunblock she was about to apply would only exacerbate that. Still, though, she felt an odd compulsion to keep going. She crept back up to Gwen and squirted out more sunblock, preparing to cover the rest of her back. Her hands glided carefully over the firm, dense muscle that now made up most of Gwen’s physique, which throbbed and swelled gently every time Gwendolyn touched it. Its firmness and enormity were astounding to Gwendolyn, and as she rubbed more and more sunblock into Gwen’s pale skin, these traits were only intensified more and more. Gwen went from having a bodybuilder physique, to having a physique that trounced bodybuilders, in just a matter of minutes. After enough sunblock was rubbed into it, Gwen’s back became just as toned as her front, and her legs and arms continued to bulk up as Gwendolyn covered their back sides. She felt her hands start to shake slightly as she continued applying it, and once she was done, she was left staring at a Gwen she never though she’d get to see. “Hmm… Feels like you’re about done. Lemme stand up…” Gwen said, forcing Gwendolyn off her beck as she climbed to her feet. Gwendolyn watched with a look of pure shock as Gwen’s new body loomed over her while she sat on the ground, occupying more space than she had ever seen it take up. She had a truly monolithic presence now, and, to Gwendolyn’s surprise, actually seemed to be enjoying it. “Mmm… that’s better,” Gwen said, stretching her huge arms over her head.

“G-Gwen… you’re...”

“Huge? Yeah, I guess you could say that,” Gwen said, smugly. “Really glad I packed that Beef-Up brand sunblock for our trip today. Feels so great to be huge…” Gwen took a moment and flexed her muscles strongly, making her body bulge out even more. Gwendolyn was totally engrossed by what she was seeing. “Looks like you like this just as much as I do,” Gwen commented, nudging the huge bulge in Gwendolyn’s black swimsuit that had been steadily rising as she had been watching Gwen’s body grow. Gwendolyn’s look of surprise quickly changed to a look of lustful satisfaction.

“Oh… I see what’s happening here. You wanted to get me all hot and bothered just so I wouldn’t get bored out here, huh?” Gwendolyn said with a smirk.

“Well, you didn’t seem all that interested in swimming…” Gwen said with a shrug. Suddenly, Gwendolyn leapt forward and tackled Gwen, pinning her to the ground.

“Even with a body like this, you’re no better at stopping me from having my way with you,” Gwendolyn said, mischievously.

“Who’s to say I want to stop you, eh?” Gwen replied with a giggle.

“Mm, temptress…” Gwendolyn moaned, pulling her foot-long erect cock out of her tight swimsuit, pulling Gwen’s strained bikini bottom out of the way of her tight pussy, and, without further warning, shoved it in.

“Aah!” Gwen moaned loudly as Gwendolyn penetrated her, her hands digging into the sand as her whole body tensed up. Gwendolyn grunted loudly as she started to thrust into Gwen’s pussy, holding onto her thick, toned arms to keep herself steady as she pounded her.

“Fuck! You’re like a million times tighter down here! You should bulk up like this more often, this feels amazing!” Gwendolyn said, her hips slapping loudly against Gwen’s meaty muscle thighs with every thrust.

“Doesn’t it? I’m so much more sensitive like this! Ooh!” Gwen moaned, even more loudly this time. As Gwendolyn thrust ferociously into her, Gwen couldn’t help but flex her muscles even more every time her girlfriend’s cock was thrust back into her. This flexing was well-received on Gwendolyn’s end, who felt her cock get squeezed and milked even harder every time Gwen flexed her monstrous muscles.

“G-Glad you grew these too, though,” Gwendolyn said, shortly before burying her face in Gwen’s huge breasts. The only part of her that was still remotely soft, Gwen’s tits provided Gwendolyn’s head with ample comfort as her hips continued to pound away at her pussy. Normally, Gwendolyn liked to turn Gwen into a trembling, mindbroken mess of a girl through multiple orgasms before she even thought about cumming herself, but this time, the unmatched tightness of her muscle-framed preteen pussy was enough to milk an orgasm out of Gwendolyn’s throbbing member far earlier than she had liked. “O-Oh shit, I’m gonna cum already… n-no!” Gwendolyn groaned, gritting her teeth as she felt her cock explode inside Gwen against her wishes.

“Ooh! You’re filling me up!” Gwen moaned, pressing Gwendolyn into herself as she made her erupt uncontrollably in her pussy. Gwendolyn’s big, full balls poured at least a full gallon of her spunk inside Gwen, an impressive amount, even by her standards. By the time she had finished, she was laying atop Gwen’s enormous body, sweating and panting heavily.

“Wow… this was one hell of a surprise…” Gwendolyn said, still somewhat out of breath.

“Hehehe…” Gwen chuckled. “You think the surprise ends here?” She leaned forward, pushing Gwendolyn off of her, and reached for the tube of sunblock that was lying idly on the ground. “We’ve still got more than half a tube of this stuff to get through. Any idea what we should do with it next?” Gwen asked, a tinge of lewdness still in her voice. Gwendolyn looked at Gwen, her throbbing muscles, her perfect tits… then down at her own body. Flat, thin, relatively uninteresting. Then she looked at the sunblock… and the gears in her head began to turn.

“Oh, I’ve got several...”


End file.
